Update README
Readme tweaks
Add config options and playbook tasks for installing pip dependencies
Change all charms to trusty series, as our pip commands wont work on precise's version
Readme tweaks: make heading sizes more logical; rewrite headings; tweak introduction; rewrite testing section
Merge branch 'readme-updates' into pip-features
Readme changes
Add config options and playbook tasks for installing pip dependencies
Change all charms to trusty series, as our pip commands wont work on precise's version
Merge branch 'master' into config-restructure